<!DOCTYPE html>
<html>
<head>
  <meta charset="UTF-8">
  <title>Document</title>
  <style>
    
  </style>
</head>
<body>
  
</body>
<script>

  const obj = {
    username:"admin",
    password:123467
  }

  console.log(obj)
  console.log(typeof obj)


  
  const str = JSON.stringify(obj)

  console.log(str);
  console.log(typeof str);
  console.log(str.username);
  console.log(str.password);

  

  const o = JSON.parse(str)
  console.log(o)
  console.log(typeof o)
  console.log(o.username)
  console.log(o.password)



  const oo = {
    class: "haha",
    if:"abc",
  }

  console.log(oo.class);
  console.log(oo.if);

  
</script>
</html>